161605520 has 40 divisors (see below), whose sum is σ = 376630656. Its totient is φ = 64487808.

The previous prime is 161605517. The next prime is 161605523. The reversal of 161605520 is 25506161.

It is an interprime number because it is at equal distance from previous prime (161605517) and next prime (161605523).

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×161605520² = 52232688188940800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161605520.

It is not an unprimeable number, because it can be changed into a prime (161605523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34859 + ... + 39221.

Almost surely, 2^161605520 is an apocalyptic number.

161605520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161605520 is an abundant number, since it is smaller than the sum of its proper divisors (215025136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161605520 is a wasteful number, since it uses less digits than its factorization.

161605520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4839 (or 4833 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 161605520 is about 12712.4159780901. The cubic root of 161605520 is about 544.6933381264.

The spelling of 161605520 in words is "one hundred sixty-one million, six hundred five thousand, five hundred twenty".